Mechanical properties of conventional structural steel and fire-resistant steel at elevated temperatures

Abstract

There has been a growing shift towards the use of fire-resistant steel (FRS) in the construction industry as a replacement for conventional structural steel (CSS). However, only limited research has been undertaken in the past on the structural properties of cold-formed FRS, especially at elevated temperatures. This paper presents the results of an experimental investigation on key mechanical properties of FRS after subjecting to elevated temperatures. The steady-state tensile tests were performed on two different types of FRS and a CSS at different elevated temperatures ranging from 100° to 800 °C with a holding time of 60 min. A total number of 99 tensile coupon test specimens were tested in this study, both at room and elevated temperatures. Important observations have been made in the paper about the performance of FRS at elevated temperatures in terms of stress-strain relationships, mechanical properties, and deformability parameters. The test results indicate the better performance of FRS compared to CSS at elevated temperature greater than 400 °C suggesting a possible application of FRS in steel structures liable to be exposed to fire conditions. Constitutive modeling for steels is also proposed for strength and stiffness properties.